Phytologia (Aiigust2007) 89(2) 167 KEYS TO THE FLORA OF FLORIDA - 16 XYRIS(XYRIDACEAE) Daniel B. Ward Department of Botany, University of Florida Gainesville, Florida 32611, U.S.A. ABSTRACT Xyris (Xyridaceae) is represented in Floridaby 19 species, two ofwhich {X. isoetifoUa, X. longisepaJa) are endemic to the state. Seven of the species are considered rare within Florida. Three species {X. chapmanii, X. isoetifoUa, X. longisepala) are rated as endangered, and one {X. scabrifolia) as threatened. Xyris difformis is believed to consist of3 varieties, andXvm elliottii of2 varieties. The nomenclatural basis for Xyris caroliniana is discussed. An amplified key is given to the Florida taxa. KEY WORDS: Xyris, Xyridaceae, Florida flora. Few genera in the southeastern United States are as readily identified as Xyris, the Yellow-eyed-grasses. Their narrow wholly- basal leaves, the solitary, compact, ellipsoid heads atop a slender scape, and the 3-petaled yellow (or white) flowers, mark this genus as no other. Yet identification to species is vastly more difficult. The very uniformity ofform that so well distinguishes this genus simultaneously blends the text-book description of one species or variety into that of another. Identification is further impeded by the few morphological characters possessed by these plants and the necessity for systematists to invoke critical but often subtle distinctions forseparation ofthe taxa. Two authors have been outstanding for their skill in recognizing the sometimes obscure features that define Xyris species. Alvan Wentworth Chapman, physician and astute botanist of Apalachicola, Franklin County, in the sequential editions ofhis Floraof 168 Phytologia (August2007) 89(2) the Southern United States (1860, 1889, 1897), identified 7 new species oiXyris in panhandle Florida. Robert Krai, beginning with the summer of 1958 devoted to collection of Florida plants (sponsored by George Cooley), has gained a mastery of the genus that has enabled him to prepare and publish a series of detailed treatments (Rhodora 62:295- 319. 1960; Sida 2:177-260. 1966; Novon 9:205-219. 1999; Flora N. Amer. 22:154-167. 2000), including a further 5 new taxa. Though the genus Xyris contains 200-400 species worldwide (D. J. Mabberley. 1997), no foreign species appears to have become established in Florida; all Florida species ofXyris are native. Xyris jupicai is the most abundant, aggressive member of the genus in the state, characteristics that suggest it may have been recently introduced. But Chapman knew it (as X. elata) in 1860, and A. Michaux used "jupicai" on a label, about 1790. Nomenclature for most Florida species of Xyris is straightforward, with the type known (and in nearly all cases examined byKrai). Only one name has generateduncertaintyanddispute. In the late 18th century the South Carolina rice planter and amateur botanist Thomas Walter published his landmark Flora Caroliniana (1788). Though 10 species of ^ym are now known in coastal South Carolina (Radford et al.. Manual ofthe Vascular Flora of the Carolinas. 1968), Walter recognized only one, his Xyris caroliniana. Walter kept no type, nor is there a specimen ofthe genus in the herbarium in London (BM) of Carolina plants prepared by his friend John Fraser. H. L. Blomquist (J. Elisha Mitchell Sci. Soc. 71:35- 46. 1955) considered X. caroliniana to be ambiguous, and for many years the name was largelydisregarded. In search for a specimen that could be interpreted as the type of Walter's Xyris caroliniana, Krai (Sida 2:236-237. 1966) located a Fraser specimen in the Lamarck herbarium, Paris (P) that he identified as X. jlexuosa. This inconspicuous dry-soil species surely isn't what Walter(1788) knew in the rice fields ofhis Santee Riverplantation, nor do its linear twisted leaves correspond to Walter's "fol. gladiatis." In a recent search (D.B.W., July 1990), X. flexuosa could not be found anywhere in the vicinity of Walter's homesite. Moreover, though Phytologia (Augiist2007) 89(2) 169 Fraser visited Walter at his Santee plantation and provided him with materials for some ofthe plants described in his Flora, the great bulk of Eraser's collections was made quite independently of Walter (Ward, Taxon 26:227-234. 1977; Sida, in press), and there is no sufficient reason for connecting the specimen of Fraser with the description by Walter. Krai's selection is thus effectively a neotype, from another location and by a different collector. But the inadequacy of Eraser's specimen as a type for Xyris caroliniana does not readily lead to an incontrovertible alternative. Xyrisflexiiosa Muhl. (1813) is unidentifiable and nude. Xyrisflexnosa Muhl. ex Ell. (1816) is well described but is superfluous since X. caroliniana is cited in synonymy. Xyris flexuosa Muhl. ex Chapm. (1860) similarly fails, with X. bulbosa Kunth (^ X. torta J. E. Sm.) in synonymy. Since these names, from their accompanying descriptions, refer to the dry-soil species, it is disappointing that they are unavailable. For the present, unsatisfying as it may be, there seems no alternative clearly betterthan the neotypification proposed by Krai. The following "amplified key"' is largely based on the documentation and conclusions in the publications ofRobert Krai, and the verbal and written supplements he has generously given me over the years. The structure and phraseology, however, are often of my own design, permitting the reader access to an independent view and a somewhat different terminology that may assist in the identification of this unique group ofFloridaplants. XYRIS L. Yellow-eyed-grasses 1. Sheath ofthe scape, with its leaflike terminal extension, equalling or exceeding the longest leaves; plants diminutive (leaves usually <5 cm. long, rarely to 10 cm.); scapes filiform. 2. Base ofleafabruptly lustrous chestnut-brown; sheath ofthe scape about equalling the longer foliage leaves; yellow-flowered. Perennial herb. Moist acid sands and sandy peats of seepage bogs and ditches. Western panhandle (e. to Liberty County); rare. Summer-fall. Xyris drummondiiMalme 70 Phytologia (August2007) 89(2) 2. Base ofleafnot differently colored; sheath clearly exceeding the longer foliage leaves. 3. Bracts ofthe spike with the outer border maroon and the edge lacerate; leaves ascending, usually narrowly linear, the apical portion usually green; plants usually in clumps with many scapes; yellow-flowered. Perennial herb. Moist acid sands of pond margins, low pinelands, clearings, and disturbed areas. South peninsula (Collier County), north to mid-panhandle (Gulf, Liberty counties); common, at times so abundant as to form a thin turf. Winter-spring. Xyris brevifolia Michx. 3. Bracts ofthe spike with outerborder not differently colored, the edge entire or minutely erose; leaves flabellately spreading, often maroon; plants usually with solitary or few scapes; yellow- flowered. Perennial herb. Moist acid sands ofpond margins and clearings in pine flatwoods. Nearly throughout; infrequent (rare in southpeninsula and western panhandle). Spring. Xyrisflabelliformis Chapm. 1. Sheath ofthe scape surpassed by the longest leaves; plants delicate to robustbut ofappreciable size (the leaves >8 cm. in length, often very much so); scapes stout or slender, but not filiform (except^, isoetifolia, with linear-filiform scapes and leaves as short as 4 cm.). 4. Keel ofthe lateral sepals prominently fimbriate, the longer strands of tissue threadlike and definitely exceeding the width of the keel (although perhaps not the width of the entire sepal); tips of lateral sepals exserted beyond the subtending bract; spikes usually >1.0 cm. long. 5. Bases ofleaves hard, lustrous chestnut-brown; ridges on scape inconspicuous, smooth to the touch; spikes narrowly ellipsoidal or lance-ovoid, somewhat lustrous; plant wiry, to 1 m. tall, with narrow, spirally twisted leaves and a bulbous base deeply buried in the substrate; yellow- or white-flowered (almost exclusively white in s. pen.), usually opening in the afternoon. Perennial herb. Moist to dry acid sands ofpond embankments, pine flatwoods, and savarmas. Nearly throughout (excl. Keys); common. Summer-fall. Phytologia (Augiist2007)89(2) 171 [Xyrisflexuosa Muhl.; Xyris pallescens (Mohr) Small, the white- flowered form;Xyris torta, misapplied] Twisted yellow-eyed-grass Xyris caroliniana Walt. 5. Bases of leaves soft, straw-colored to pale green or pinkish; ridges on scape prominent, harsh to the touch; spikes ovoid or broadly ellipsoidal, dull brown; plant robust, to 1.5 m. tall; yellow- flowered, opening in the morning. Perennial herb. Ditches, wet pinelands, shallow ponds, usually with the base of the plant submersed. North Florida, south to mid-peninsula (Lake Okeechobee); infrequent. Summer-fall. Xyrisfimbriata Ell. 4. Keel ofthe lateral sepals variously ciliate to lacerate or entire, the longer strands oftissue either shorter than the width ofthe keel or, if longer, ragged and not forming fimbriate threads; tips ofthe lateral sepals exserted ornot. 6. Tips of at least some of the lateral sepals slightly to conspicuously exserted beyond the subtending bract. 7. Leaves 5-15 mm. broad; plant robust, the scapes to 1.5 m. tall; seeds >0.7 mm. long; yellow-flowered. Perennial herb. Shallow standing water of cypress ponds, lake shores, wet prairies, and ditches, with the base ofplant submersed. Nearly throughout (excl. Keys); infrequent. All year. If lateral sepals are not observed as exserted, this may be mistaken forX.jupicai from which it is separated by its larger size and usually pinkish basal coloration. Xyrissmalliana Nash 7. Leaves 1-2 mm. broad; plant slender, almost delicate, yet tall, the scapes to 0.8 m. in height; seeds <0.3 mm. long; yellow- flowered. Short-lived perennial herb, or annual. Exposed sandy shores of fluctuating karst-pond lakes. West and central panhandle (e. to Leon County); rare. Summer. Endemic. ENDANGERED (State listing). Xyris longisepala R. Krai 6. Tips of lateral sepals not exserted beyond the subtending bract (only appearing exserted ifdetached, as in old or dried spikes). 172 Phytologia (August2007) 89(2) 8. Leaves narrowly linear to filiform (<2 mm. wide); base of leaves hard, dark brown, often lustrous; spikes <1 cm. long (occasionally somewhat more in X. elliottii); plants growing in large tufts withmany scapes. 9. Keel of lateral sepals with irregular, jagged or torn edge; leaves narrowly linear to filiform, 10-30 cm. long; spikes with numerous, tightly imbricated bracts; staminodia bearded or not; seeds various. 10. Staminodia bearded (and visible as a tangle ofyellow threads in the open flower); seeds 0.5-0.6 mm. long; yellow- flowered. Perennial herb. Sandy soils ofroadside ditches, pondmargins. Spring-summer. Xyris elliottiiChapm. a. Leaves narrowly linear (1-2 mm. wide), pale to near- white on edges. Throughout; common to abundant. var. elliottii a. Leaves filiform (<1 mm. wide), lacking or with inconspicuously paler edges. Throughout; frequent to common (less frequent overall than var. elliottii, but locally predominant in central peninsula and western panhandle). var. stenotera Malme 10. Staminodia beardless (without tangle ofyellow threads in the open flower); seeds 0.8-1 mm. long; leaves filiform (<0.5 mm. wide); yellow-flowered. Perennial herb. Moist sands of pine flatwoods and roadside ditches. Panhandle and north Florida (s. to Levy, Marion counties); infrequent. Spring. Xyrisbaldwiniana Schult. in Roem. & Schult. 9. Keel oflateral sepals with regularly spaced, short, cilia-like teeth; leaves filiform (<0.5 mm. wide), relatively short (4-15 cm. long); spikes with few, loosely imbricated bracts; staminodia bearded (with a tangle of yellow threads in the open flower); seeds <0.5 mm. long; yellow-flowered. Perennial herb. Moist sands or sandy peats ofsavanna bogs, flatwood pond margins, lake shores. Central panhandle (Bay, Phytologia (August2007) 89(2) 173 Gulf, Washington counties); very local and rare. Spring- ENDANGERED summer. Endemic. (State listing). Xyris isoetifolia R. Krai 8. Leaves linear but not narrowly so (>2 mm. wide); base of leaves soft (fibrous in X. amhigua), pink, pinkish-purple, straw- colored, greenish, or brown to blackish (but not lustrous); spikes >1 cm. long (frequently less in X. jupicai and X. difformis); plants with solitary or few scapes (or in large clumps in X. stricta andX. serotina). 11. Keel of lateral sepals with regularly spaced, short, cilia- like teeth; old leaf bases persisting as blackened or brown shreds; plants robust, at times forming largeclumps. 12. Edge of leaves strongly papillate, the individual protrusions usually several times as long as wide; leaves usually spreading, less than one-halfthe height ofthe scape, drying to uniform brown or tan, the inner leafbases without dark veins; petals 8-10 mm. long, yellow, the flowers opening in the early morning; seeds translucent. Perennial herb. Moist sandy or peaty soils of pine flatwoods, savannas, roadside ditches. Panhandle and peninsula (s. to Collier, Palm Beach counties); frequent to common. Summer-fall. Xyrisambigua Beyr. ex Kunth 12. Edge of leaves mildly papillate or merely roughened, the protrusions low and rounded; leaves usually erect and more than one-half the height of the scape, drying to dark pinkish-brown, the inner leafbases with dark veins against a pale surface; petals 4-5 mm. long, yellow, the flowers opening in late morning; seeds opaque, yellow. Perennial herb. Summer-fall. Xyrisstricta Chapm. a. Leaves 3-8 mm. broad, clearly papillate. Very wet sandy or peaty soils of cypress-gum swamps and low flatwoods, the plant base often submersed. Central panhandle, disjunct to upper east coast (Flagler, Volusia counties); infrequent. var. stricta 174 Phytologia (August2007) 89(2) a. Leaves 2.5-3 mm. broad, smooth to slightly papillate. Moist sandy peats or clays, never immersed. West panhandle (e. to Liberty County); rare. [Xyris louisianica Bridges & Orzell] var. obscura R. Krai 11. Keel oflateral sepals with irregular,jagged or torn edge; old leaf bases soft and not persisting; plants robust to small and slender. 13. Leaves and scapes markedly spirally twisted above, pinkorpurplish (infrequently ivory) towardbase. 14. Plants slender (leaves 2-4 mm. wide); lowest portion of leafnot conspicuously thickened; base ofplant deeply buried but not bulbous; leaves smooth, the outermost not appreciably shorter than others; flowers opening in the late morning; petals ca. 3 mm. long, yellow. Perennial herb. Deep muck of acid bogs. Western panhandle (Munson, Santa Rosa County); very rare. ENDANGERED (State listing). Xyris chapmaniiBridges & Orzell 14. Plants robust (leaves 5-10 mm. wide); lowest 1-2 cm. of each leaf thickened and fleshy, forming a bulb-like enlargement at base of plant (more conspicuous when fresh); usually a few outennost leaves very short (1 to 2 times as long as wide), spoon-like around the swollen base; flowers opening in the afternoon; petals ca. 5 mm. long. 15. Leaf and scape surfaces smooth; plants tall (the scape to 1 m.); flowers usually white, sometimes yellow, the petals obovate; seeds <0.6 mm. long. Perennial herb. Wet acid sands, pine flatwoods, grassy savannas, pond margins, ditch banks, quickly occupying cleared and disturbed soils. Panhandle, south to mid-peninsula (Lee, Martin counties); common. Summer-fall. Xyrisplatylepis Chapm. Phytologia (August2007) 89(2) 175 15. Leaf and scape surfaces prominently papillose or tuberculate-scabrid, the foliage appearing glazed or glassy; plants medium (the scape seldom above 0.5 m.); flowers yellow, the petals suborbicular; seeds 0.6-1 mm. long. Perennial herb. Moist to wet sandy peats of acid bogs or seepage slopes. West and central panhandle (Escambia, Washington, Calhoun, Bay counties); rare. Summer-fall. Endemic. Threatened (State listing). Xyrisscabrifolia Harper 13. Leaves and scapes not markedly spirally twisted, tan or pinkish towardbase. 16. Scape flattened and 2-edged, in cross section narrowly elliptic, the edges smooth; spike usually >2 cm. long; plants robust (leaves 10-25 mm. wide); base ofplant pink to purplish; yellow-flowered. Perennial herb. Emergent from shallow water at edge of streams or flatwood ponds, usually on clayey soils. Western panhandle (e. to Jefferson County), disjunct to northeast Florida (St. Marys River, Nassau County); rare. Summer- fall. [Xyris iridifolia Chapm.] Xyrislaxifolia Mart. var. iridifolia (Chapm.) R. Krai 16. Scape terete, with 2-several ridges sharply distinct from the scape-body, the edges papillate-scabrid or smooth; spikes usually <1.5 cm. long; plants medium to small (leaves <15 mm. wide). 17. Plant base pink to purplish (sometimes faded in dried material; not to be confused with pigment- congested cells of upper leaves and scape), if pigment absent, ridges on scape broad (each oflarger ridges half or more the width ofthe scape-body); yellow-flowered. Perennial herb. Seepage bogs, acid pond margins, wet ditchbanks, and along streams in bottomland woods. Summer-fall. Xyrisdifformis Chapm. 176 Phytologia (Augiist2007) 89(2) a. Surface ofleaves smooth; scape ridges usually 2, infrequently 3, the edges papillate-scabrid to nearly smooth. Western panhandle (e. to Jefferson County); infrequent. var. difformis a. Surface of leaves, particularly the outemiost, papillose or tuberculate-scabrid; scape ridges usually >3, the edges papillate-scabrid. b. Plants usually over 20 cm. tall, the leaves 10-30 cm. long; seeds opaque, farinose. Peninsula (s. to Lake Okeechobee); frequent. vsLr.JJoridana R. Krai b. Plants usually under 20 cm. tall, the leaves less than 10 cm. long; seeds translucent, non-farinose. North and mid-Florida (Duval, Charlotte, Dade counties); rare. [Xyris neglecta Small] var. curdssii(Malme) R. Krai 17. Plant bases green to straw-colored or blackish, without pink coloration; ridges of the scape narrow (much less thanhalfthe width ofthe scape-body). 18. Scape with 2 ridges (shortlybelow the spike), the edges smooth or very nearly so; plants pale green or straw-colored toward the base; yellow-flowered. Annual or short-lived perennial herb. Wet sand of ditches, clearings, prairies, pond margins, and lakeshores, often in disturbed areas. Throughout; common, sometimes locally abundant. Summer-fall- winter. [Xyris communis Kunth;Xyris elata Chapm.] XyrisjupicaiL.Rich. 18. Scape with 2 primary and 2-several secondary ridges, the edges clearly scabrous; plants dark brown or blackish toward the base; yellow-flowered. Perennial herb, usually in large clumps with many scapes. Wet sandy peat at edge ofcypress ponds or flatwoods depressions. Western panhandle (e. to

Keys to the flora of Florida - 16 Xyris (Xyridaceae)

Similar Keys to the flora of Florida - 16 Xyris (Xyridaceae)